Technical Field
Embodiments of the present disclosure relate to a driving circuit of a switching device for an electric power control, and more particularly, to a driving circuit of a switching device for an electric power control capable of improving reliability of an ON/OFF driving and a status monitoring.
Description of the Related Art
For controlling electric power being supplied to an alternating current motor, a semiconductor switching device for an electric power control, such as an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET) and the like, is used for an electric power conversion or an electric power control in which an alternating current is converted into a direct current and the direct current is again converted into the alternating current through an inverter.
The present disclosure relates to a driving circuit of such a semiconductor switching device for an electric power control.
In a driving circuit of such a semiconductor switching device for an electric power control, the related art will be described below with reference to FIG. 1.
As shown in FIG. 1, a driving circuit of a semiconductor switching device for an electric power control according to the related art is configured to include a driver circuit unit 20 and a control circuit 10.
In FIG. 1, a reference numeral 30 is a semiconductor switching device (hereinafter, referred to as a switching device) which is a target of an ON or OFF driving of a driving circuit.
The switching device 30 may be typically configured with the IGBT or the MOSFET described above.
The switching device 30 may have an emitter, a gate, and a collector, and may be turned on or off according to a voltage difference between the emitter and the gate. For example, the switching device 30 is turned on when a voltage difference between the emitter and the gate is in a range of 12 to 20 volts (V), whereas it is turned off when the voltage difference between the emitter and the gate is in a range of 0 to 11 V.
Also, when the switching device 30 is in an ON state, a voltage difference between the emitter and the collector is decreased from ten to tens of volts in an OFF state to 2 to 3 volts, and it may be determined whether or not the switching device 30 is in an ON state by detecting a collector voltage. However, according to an amount of current flowing between the emitter and the collector, a variation of a voltage difference therebetween may occur.
The driver circuit unit 20 is connected to the gate and the collector of the switching device 30, and is a circuit unit which outputs a driving signal to the gate to drive the switching device 30 to an ON state or stops the outputting of the driving signal to change the switching device 30 from the ON state to an OFF state. Here, the driving signal may be a current signal of, for example, about several amperes, or a voltage signal of, for example, ten to tens of volts.
The driver circuit unit 20 may be configured with an integrated circuit for outputting the driving signal.
The driver circuit unit 20 may receive a voltage detection signal representing a collector voltage value of the switching device 30 from the collector thereof.
A reference numeral 40a represents a transmission side circuit which transmits the voltage detection signal to the driver circuit unit 20.
In FIG. 1, a reference numeral 40 represents a protective diode of the transmission side circuit 40a, which is conducting when a voltage of the transmission side circuit 40a is higher than a collector voltage of the switching device 30.
Also, the driver circuit unit 20 provides the control circuit 10 with the collector voltage value according to the voltage detection signal received from the collector of the switching device 30 and a monitoring signal representing a state of the driver circuit unit 20. Further, in FIG. 1, an arrow indicating a left side between the driver circuit unit 20 and the control circuit 10 shows a transmission of the monitoring signal.
The control circuit 10 is connected to the driver circuit unit 20 to output an ON or OFF control instruction signal regarding the switching device 30 to the driver circuit unit 20. In FIG. 1, an arrow indicating a right side between the driver circuit unit 20 and the control circuit 10 shows a transmission of the ON or OFF control instruction signal.
Therefore, the control circuit 10 may determine a current ON/OFF state of the switching device 30 and a current state of the driver circuit unit 20 based on the monitoring signal provided from the driver circuit unit 20.
However, the driving circuit of a semiconductor switching device for an electric power control according to the related art is configured to perform an ON/OFF driving and a state monitoring of the switching device 30 by means of only the single driver circuit unit 20. Consequently, when a malfunction such as a burning of the single driver circuit unit 20 occurs, there is a problem in which the ON/OFF driving and the state monitoring of the switching device 30 are broken down.